The present invention relates to a data cartridge tape drive and specifically to a half height cartridge tape drive having a pivotal deck which engages and aligns the cartridge with the magnetic head upon rotation of the pivotal deck into engagement with the cartridge.
Data cartridges for use in storing digital information for use in computer applications are known. Such cartridges incorporate a length of magnetic recording tape which is wound between a pair of spools or reels which are rotated by a belt which moves in response to rotation of a drive roller. A typical belt driven tape cartridge of the type utilized in the present invention is shown in U.S. Pat. No. 3,692,255 which shows a two spool tape cartridge in which a flexible belt extends around guide rollers adjacent the pair of spools and a drive roller between the spools. Rotation of the drive roller causes the belt to drive the tape spools to provide proper tensioning of the tape and to move the tape between the spools. Access to the magnetic tape in the cartridge by a magnetic head is provided through an opening along one edge of the cartridge. When not in use, the tape is protected by a pivotal door which closes over the opening.
A cartridge of this configuration permits bidirectional drive and rapid acceleration and deceleration of the tape which is a requirement of tape cartridges used in computer applications.
Cartridge tape drives for such cartridges are known. Such tape drives typically incorporate a drive mechanism which contacts the drive roller of the cartridge to effect rotation of the spools on which the magnetic tape is wound. Additionally, conventional cartridge tape drives include a magnetic head which may or may not be vertically movable to contact different tracks on the tape, positioned to contact the magnetic tape passing through the opening in the edge of the cartridge. Such cartridge tape drives also provide some manual or automatic mechanism for pivoting the door over the edge opening in the cartridge to enable magnetic head access to the exposed portion of the magnetic tape passing through the opening. Conventional cartridge tape drives further include an indexing or registration mechanism for precisely positioning the cartridge, and hence the tape, relative to the magnetic head, so that the magnetic head will contact the magnetic tape at a predefined location and orientation so as to enable reading of data from and writing data onto the magnetic tape.
Cartridge tape drives have also included a head positioning mechanism for vertically positioning the magnetic head relative to the tape to position the head opposite selected tracks on the magnetic tape so as to enable reading data from or writing data onto that particular track.
Conventional cartridge tape drives having one or more of the above described features have generally had a height of 31/4" or greater where the magnetic head, the various indexing and registration pins and the like are fixed as part of the cartridge tape drive so that registration between the head and the cartridge must be accomplished by movement of the cartridge itself.
Proposals to incorporate a moveable deck on which the magnetic head is fixed involve a different class of problems. For example, registration pins, when not fixed to the movable deck, may become misaligned relative to the deck and hence the magnetic head. Alignment of the cartridge with the registration pins may result in imprecise positioning of the head with the tape in the cartridge. The fact that the head can move relative to the registration pin therefore presents difficulties in achieving and maintaining the alignment precision necessary for positioning the head relative to the tape in the cartridge. Furthermore, proposals for locating the head on a moveable deck have generally included proposals for additional complex mechanisms which work in conjunction with the movable deck to position the cartridge and thereafter hold the cartridge in a precise fixed orientation relative to the head when the deck has moved into a predefined engagement position. Additionally, prior art devices as well as proposed movable deck devices have required cartridge door opening mechanisms which require pre-opening of the door before or as a part of the insertion of the cartridge into the cartridge tape drive. Finally, all of the above problems and features are amplified and exaggerated when it is desired to have a cartridge tape drive which is not of a conventional height of 31/4" but of half that height, that is, 15/8".
Accordingly, the present invention provides a half height data cartridge tape drive incorporating a pivotal deck which pivots through an arc of 121/2.degree. and on which are mounted, in fixed horizontal relationship to each other, the index (registration) pins and the magnetic head. The magnetic head is provided with a head positioning mechanism which permits precise, non-arcuate, vertical movement of the magnetic head relative to the tape to precisely position the head at a pre-defined vertical track on the tape. The present invention further provides a half height cartridge tape drive which precisely positions and aligns the data cartridge, after the cartridge has been fully inserted, solely as a consequence of pivotal movement of the deck into the engaged position. The tape drive of the present invention includes a manually actuated level. As the lever is moved toward the engaged position, a door opening mechanism is incorporated to open the door. After the door is fully opened, further movement of the lever initiates pivotal movement of the deck whereby the magnetic head is rotated into engagement against the magnetic tape.
The pivotal deck, side walls of the tape drive housing, and the top of the tape drive housing include precisely placed pads, ramps, cams and other positioning devices positioned in coordination with indexing pins and surfaces on the deck to effect precise orientation and positioning of the cartridge relative to the deck and hence to the magnetic head. These pads, ramps, cams, index pins and index surfaces cooperate with the pivoting the deck without the need of separate mechanical linkages to effect positioning of the cartridge. Hence, movement of the manual lever effects, in precise sequence, the opening of the cartridge door, the horizontal positioning of the cartridge relative to the head, and the precise vertical registration of the cartridge relative to the head, all as an integral consequence of pivoting the deck into an engaged position.
Additionally, the present invention provides for a novel ejection linkage as well as a novel vertical head positioning mechanism whereby the head may be moved in a precise vertical direction rather than in an arcuate manner relative to the magnetic tape when the head is in contact with the magnetic tape. Finally, the present invention incorporates a novel drive mechanism which incorporates a stretched drive tire over a drive capstan, which stretch drive tire contacts the drive roller of the cartridge to effect rotation of the spools and hence movement of the magnetic tape of in the cartridge. The stretched drive tire permits a smaller change in drive roller velocity in response to variations in the pressure applied against the drive roller by the drive capstan to enable greater precision in data transfer between tape and magnetic head.